Known in the art are different types of a sprinkler applied in fire extinguishing equipment. These prior art devices differ both in types of thermally responsive units used as their structural components and channel configuration through which the fire extinguishing liquid is supplied.
For instance, known in the art are sprinklers having a body with an axial cylindrical channel for liquid supply, a thermally responsive unit with a valve closing the sprinkler outlet, and a thermally responsive unit attachment (patent U.S. Pat. No. 5,392,993, B05B 1/26, published Feb. 28, 1995). The design feature of this sprinkler is configuration embodiment of a liquid stream diffuser element fixed opposite the channel outlet. The improvement described in U.S. Pat. No. 5,392,993 has been designed to generate a gas-and-drop stream of a certain spatial configuration, which is the most optimum one for fire extinguishing, as well as a drop size change in the stream generated and their specific distribution (by their size) in the stream generated. However, this technical decision is characterized by a complex structure and limited possibilities.
Known in the art are also other technical decisions, among which another sprinkler may be noted described in U.S. Pat. No. 4,800,961 (A62C 37/10, published Jan. 1, 1989). A common sprinkler has a body with liquid supply channel, a thermally responsive component with a valve closing the sprinkler outlet and thermally responsive unit attachment. The sprinkler channel is formed by a few sequentially connected segments of different shape and different passage cross-section. The first segment of the channel from the liquid supply side is a conical diffuser with an aperture angle of about 8°. The first segment is connected to the second one having the form of a conical diffuser with an aperture angle of about 60°. The third segment of the channel is of a cylindrical shape, the diameter of which equals to that of conical diffuser outlet cross-section. The diffuser channel outlet is formed by an annular projection. A flat surface of the annular projection having a minimum longitudinal size is oriented perpendicular to a liquid stream direction in the sprinkler channel. This configuration of sprinkler channel embodiment provides generation of larger drops on account of a stream speed decrease at the channel outlet. As a result the sprinkler produces a gas-and-drop stream with a desired liquid distribution by its drop sizes for effective extinguishing. Large drops are in the central part of the stream, which is directly used for extinguishing the flame. The drops of a relatively small size are in the peripheral part of the gas-and-drop stream to reduce the smoke gas temperature or cool the environment.
The sprinkler structure described allows, on the whole, to reduce non-productive liquid consumption. However, a part of energy inputs for gas-and-drop stream generation is non-productively spent in braking a peripheral part of the liquid stream at the cylindrical portion of the channel in front of the annular projection.
The most closely analogous device of the first alternative embodiment of the invention is a sprinkler described in the Author's Certificate USSR NQ 643162 (A62C 37/12, published Jan. 1, 1979), which has a body with a liquid supply channel, a thermally responsive unit with a valve, which closes the sprinkler outlet, and the thermally responsive unit attachment. The sprinkler channel is formed by a segment of a cylindrical shape connected with a segment in the form of a conical diffuser. However, the sprinkler channel dimensions and configuration were not optimized in the said structure, which is necessary for effective liquid spray over the fire site. Together with this the prior sprinkler does not allow to generate a uniform finely-dispersed gas-and-drop liquid stream of a high kinetic energy of the drops at the fire surface.
The most closely analogous device of the second alternative embodiment of the invention is a sprinkler described in a European application EP 0701842 A2 (A62C 37/08, published Mar. 3, 1996), which has a body with liquid supply channels, a thermally responsive component with a valve, which closes the sprinkler outlet, and the thermally responsive component attachment. One of the sprinkler channels is made in the form of an axial cylindrical channel, the length of which exceeds its diameter, and the second one in the form of an annual channel with helical guide components coaxial to the first channel. This technical decision is aimed at a gas-and-drop stream generation with an optimum size of the drops and uniform distribution in space, which allows to effectively use the liquid for fire extinguishing. It should be noted that the structure of the prior art sprinkler does not provide effective fire extinguishing on a large area, as at the sprinkler outlet a gas-and-drop stream is generated, the cross-section of which is limited by the edges of a common outlet. In this case it is required to increase sprinkler arrangement density on the ceiling of the room.